DE69912430T2 - hydroformylation - Google Patents

Description

The present invention relates to a method of performing of hydroformylation reactions. In particular, the present concerns Invention the hydroformylation reactions by heterogeneous Catalysts in almost critical or supercritical fluids be catalyzed.

background

The use of carbon monoxides as Reagent for The organic synthesis is diverse, with a large number of reactions carried out becomes. A process of large-scale The importance is the hydroformylation (also known as the "oxo" process), the for large-scale production of aliphatic aldehydes and alcohols from olefins (alkenes) using homogeneous catalysts based on cobalt or rhodium is applied.

Generally, the hydroformylation reaction involves the reaction of an alkene or alkyne with a mixture of carbon monoxide and hydrogen over a catalyst under high pressure to a carbonyl compound to create. Mixtures of hydrogen and carbon monoxide are often called Designated syngas or syngas.

1 generally shows the hydroformylation of an alkene. The resulting carbonyl compound, which can be the normal (n) or iso product, can then be reduced to give the corresponding alcohol. An alternative way is to first convert the alkene or alkyne into a trialkylborane or trialkylboron and then convert this product with carbon monoxide and a reducing agent.

It is well known that reactions this to solubility the gases in the liquid Reagent or solvent are limited (as Mass Transport Limitations = mass transport limits known). For environmental reasons is gradually on the use of supercritical fluids instead of conventional ones Solvents passed. The use of supercritical fluids as the reaction media results Moreover higher solubilities of gases in the system and effectively a higher activity of these reagents by overcoming the mass transportation limits.

• 1) die Hydroformylierung von Olefinen, Chemtracts: Org. Chem. 1996, 9 (6), 318–321, und Chemtracts: Inorg. Chem. (1995), 7 (2), 129–123;
• 2) über die Hydroformylierung von Propylen in einem Chargensystem, bei dem die homogene Katalyse in superkritischen Fluiden angewandt wird, wird berichtet von Akgerman et al. (Fourth Italian Conference on Supercritical Fluids and their Applications, September 1997 Proceeding, Seiten 263–269);
• 3) US 5 198 589 beschreibt einen Chargen- oder kontinuierlichen Chargenprozeß, bei dem die homogene Katalyse angewandt wird.

So far, batch systems have been used that use homogeneous catalysts in supercritical fluids. Examples of known heterogeneous hydroformylation reactions are given below:

• 1) the hydroformylation of olefins, Chemtracts: Org. Chem. 1996, 9 (6), 318-321, and Chemtracts: Inorg. Chem. (1995), 7 (2), 129-123;
• 2) The hydroformylation of propylene in a batch system using homogeneous catalysis in supercritical fluids is reported by Akgerman et al. (Fourth Italian Conference on Supercritical Fluids and their Applications, September 1997 Proceeding, pages 263-269);
• 3) US 5,198,589 describes a batch or continuous batch process using homogeneous catalysis.

The use of homogeneous catalysts and batch processes however, problems of catalyst separation, a long residence time and scale-up risks. With those in these publications described method it is actually a fairly significant one Problem that the Using homogeneous catalysts a separation step required at the end of the process to recover the catalysts, because this makes additional Processing steps required and thus increases costs. Further is a separation in the case of alkenes whose chain length is longer than C7 is particularly difficult since separating the catalysts from the products require high temperatures by distillation, which destroy the catalysts. As a result, can these processes that use alkenes whose chain length is longer than C7 is not to be carried out in continuous reactors (flow tube reactors).

The use of homogeneous catalysts also means that this Procedure usually be carried out in batch or semi-continuous reactors. Such conditions require due to the design requirement of containers, which can be operated under high pressure, extensive capital expenditure during scale-up. The use of batch systems also has the Disadvantage increased Downtime for loading and emptying the reaction container. There is also that Problem that that Product of the reaction due to the long residence time of the reactants in the reactor a mixture of thermodynamic and kinetic Products.

In the past with heterogeneous catalysis for Hydroformylations under conventional (i.e. H. almost critical or supercritical) conditions worked Service. However, these reactions have never been successful, usually because of low conversion to products and catalyst deactivation. About heterogeneous catalyzed hydroformylation reactions in supercritical Media performed has not been reported so far. Because of this, Time on an industrial scale no hydroformylation reactions using a heterogeneous Catalyst carried out become.

So there is a need for a hydroformylation process in which the catalyst is easily obtained by simple filtration can be separated from the product. Ideally, that should be Allow procedures that the Separation even in hydroformylations of alkenes, alkenes or Trialkylboranes is achieved, the chain length is longer than C7.

There is also a need for a hydroformylation process in which a continuous reactor (flow tube reactor) is used can be. Ideally, the procedure should move the operator into the Relocate, the dwell time and the other reaction parameters independently control to allow better control of the response. It also exists a need for a process that is more efficient and / or more selective than conventional ones Procedure is.

Surprisingly we found that the Hydroformylation of alkenes, alkynes and trialkylboranes under Use of a heterogeneous catalyst in supercritical media accomplished can be. By using a combination of a supercritical Medium that has one or more components and a heterogeneous Catalyst (e.g. the Deloxan HK1 2% rhodium complex catalyst from Degussa) it is possible To carry out hydroformylation reactions with high conversion. It is also possible the reaction with good selectivity for the n or iso products perform, whereby the possibility exists to form both the normal and the iso products. The present invention solves So the problems of the prior art by the hydroformylation reaction under conditions near or above the supercritical point of the reaction medium in the presence of a heterogeneous catalyst is carried out in a continuous reactor.

According to the present invention a method for hydroformylating a substrate is provided, the substrate being selected from alkenes, alkynes and trialkylboranes and with hydrogen and carbon monoxide in the presence of a heterogeneous one Catalyst is implemented, wherein the substrate has a fluid in its supercritical or almost critical condition and / or the Implementation in the presence of a solvent for the Substrate runs out, being the solvent is in its supercritical or nearly critical state, and the process being carried out in a continuous reactor. The yield and / or selectivity implementation may be affected by controlling one or more of the reaction conditions: Temperature, pressure, residence time, flow rate and catalyst.

In one embodiment, the catalyst following on a carrier, the selected is made of: an organosiloxane polycondensate, an organosiloxane copolycondensate or polymeric secondary and / or tertiary Organosiloxanamine combinations; and a metal or a metal complex in which the metal is selected from: platinum, nickel, palladium, cobalt, rhodium, iridium, iron, Ruthenium and being osmium; and the catalyst has optional an accelerator. Rhodium is a particularly preferred metal.

Suitable catalysts therefore have Deloxan HK1, which is a 2% Rh catalyst available from Degussa on a polyaminosiloxane support is.

The hydroformylation reaction of the present invention is sufficient the above requirements by providing a procedure in which the products can be easily removed from the Catalyst can be separated. This applies to Reactions on alkenes, alkynes or trialkylboranes, the chain length of which is longer than Is C7. Alkenes, alkynes or trialkylboranes, the chain length of which is longer than C7 is, can be hydroformylated, and the products can be easily obtained from be separated from the catalyst without distillation or further Refurbishment is required.

The method also results in Yields and selectivities, that are better than conventional methods. The characteristic of selectivity is an important characteristic of Invention since the iso product is common is a by-product of hydroformylation reactions, which can be found under usual Conditions carried out in cases where in which the generation of both normal and iso compounds is possible. The method of the present invention can thus occur significantly reduce the iso product if desired. In some cases can the iso product the desired Be a product; in this case the reaction conditions for the ISO product can be optimized.

The method of the present invention allows also the implementation the reaction in a flow tube reactor. The use of a flow tube reactor has the advantage that one Always a small inventory of reagents under high pressure has, so that the overall security of the process is increased.

We also found that the reactor under such conditions can be made very efficient by only half the amount of synthesis gas used by Akgerman et al. in the explained Procedure needed becomes. Surprisingly results in a change the pressure in the reactor a selectivity in relation to the ratio from n to iso products (this is shown in Table 1 below) is given in connection with Example 1). By change of the pressure of the supercritical medium it is therefore possible to use ratios of greater than Get 3: 1 of the n-: Iso products.

In the process of the present invention, at least one of the components other than hydrogen or carbon monoxide is under supercritical or near critical conditions. One or more of temperature, pressure, flow rates, and hydrogen and carbon monoxide concentrations can be controlled independently for a given catalyst to affect the selectivity of the reaction. The catalyst can also be altered (either with a given set of conditions or under different conditions of temperature, pressure, flow rate, etc.) to affect the selectivity of the product.

• (a) Beimischen einer inerten Fluidmenge zu einer Menge des Substrats und einer Menge an Wasserstoff und Kohlenmonoxid bei vorbestimmten Durchflußraten;
• (b) Einstellen der Temperatur und des Drucks des resultierenden Gemischs auf vorbestimmte Temperatur- und Druckwerte nahe oder über dem kritischen Punkt des Fluids, um ein Reaktionsgemisch zu erzeugen, aus dem das gewünschte Carbonylprodukt als das Haupt-Carbonylprodukt gebildet wird, wobei die Wahl der vorbestimmten Temperatur- und Druckwerte davon abhängt, welches der möglichen Hydroformylierungsprodukte gebildet werden soll;
• (c) das Reaktionsgemisch wird einem heterogenen Katalysator ausgesetzt, um die Reaktion zu erleichtern; und
• (d) das Reaktionsgemisch wird nach der Reaktion aus dem Bereich des Katalysators entfernt und das gewünschte Produkt wird durch Druckabbau des Reaktionsgemisch isoliert.

The alkene, alkyne or trialkylborane substrate is hydroformylated in a continuous process, which preferably has the following steps:

• (a) admixing an inert amount of fluid with an amount of the substrate and an amount of hydrogen and carbon monoxide at predetermined flow rates;
• (b) adjusting the temperature and pressure of the resulting mixture to predetermined temperature and pressure values near or above the critical point of the fluid to produce a reaction mixture from which the desired carbonyl product is formed as the main carbonyl product, the choice of predetermined temperature and pressure values depend on which of the possible hydroformylation products is to be formed;
• (c) the reaction mixture is exposed to a heterogeneous catalyst to facilitate the reaction; and
• (d) the reaction mixture is removed from the region of the catalyst after the reaction and the desired product is isolated by reducing the pressure of the reaction mixture.

The heterogeneous flow system of the present invention offers a number of advantages in comparison with batch type systems or with a homogeneous continuous system. In particular, the present invention the formation of a desired end product with a good yield and / or selectively by adding one or more is controlled by the following: the temperature, the pressure of the reaction through change of for a given set of reagents used catalyst that flow through the device and the molar ratios of hydrogen and carbon monoxide to the substrate.

The factors affecting the selectivity of hydroformylation determine hang depending on the reaction, and in some cases the temperature is or pressure is the controlling factor, whereas in other cases the Catalyst or the flow rate may be more important in determining the reaction result. According to the present invention, there are suitable conditions for a given substrate and a desired one Product determined.

The present invention provides also the advantage that dangerous Reagents can be used without that a high level of reagent is required at any time as the organic compound and the hydrogen and carbon monoxide fed continuously to the reactor become.

Likewise, the reaction product or the reaction products are continuously collected from the reactor and therefore do not accumulate in large quantities in the reactor. This has the further advantage that a lower risk of There is degradation of the products. This is accompanied by an increase in Safety of the process in comparison with a batch process, if dangerous Reagents used or dangerous Products are made because these materials are usually not are present in amounts sufficient to pose a significant risk display. Because the continuous process of the present invention also the implementation of cleaner reactions than with a corresponding procedure batch type enables will the cost of reduced cleaning of the products.

The present invention has the further advantage that higher yields and higher throughputs than in some cases with conventional Procedure can be obtained. The actual throughputs inevitably depend the particular reaction being used and the size of the device ab, but there are throughputs of 25 ml / min or more available when using laboratory scale devices. In addition, at Applying the method of the present invention easily selectivities of received more than 3 to 1 in favor of the normal carbonyl product become.

The hydroformylation reaction of the present invention is carried out near or above the supercritical point of the desired medium. Any fluid that has a supercritical point can be used in the method of the present invention provided it is compatible with the reactants. In addition, alkene, alkyne or trialkylborane (if not a solid) can be both the substrate and the supercritical medium. In practice, however, the choice of fluid depends on the solubility of the substrate in the fluid, since it is a function of the supercritical or near critical fluid to be effective as a solvent for the substrate and the hydrogen and carbon monoxide. It is also important that the reaction medium be inert with respect to the reactants and the products of the reaction in order to avoid undesirable side reactions. Particularly preferred media include: carbon dioxide, sulfur dioxide, alkanes such as ethane, propane and butane and saturated halogenated hydrocarbons such as trichlorofluoromethane, dichlorofluoromethane, dichlorodifluoromethane, chlorotrifluoromethane, bromotrifluoromethane, trifluoromethane and hexafluoroethane. The reaction medium can be a mixture of be two or more fluids that have critical points that do not require technically unacceptable temperature and pressure conditions to achieve the conditions required for the reaction of the present invention. For example, mixtures of carbon dioxide with an alkane such as ethane or propane or a mixture of carbon dioxide and sulfur dioxide near or above their theoretical critical points can be used.

In connection with the present Invention, however, form temperature and pressure conditions near the critical point, the lower limit of the conditions for support the hydroformylation reaction are suitable. If a fluid its reached critical point, its density is relative to its density significantly reduced at its boiling point under normal pressure. low pressure changes near the critical point cause additional changes in density. The procedure is in the fluid at temperatures and pressures below the critical point feasible however, the density of the fluid is sufficient to ensure that this Substrate and the hydrogen and carbon monoxide essentially are in a single phase. The upper limit of temperature and Pressure is determined by device limitations.

While it is more difficult among those Reaction conditions used in the present invention are to hydroformylate aliphatic compounds as aromatic Compounds, however, according to the present invention is hydroformylation both aliphatic and aromatic compounds possible.

Product formation can be done in situ with Using IR spectrometry using an appropriately positioned IR high pressure cell or monitored using gas chromatography (GC) be made on samples taken from the reactor become.

The present invention is as follows described only by way of example with reference to the figures. This show in:

1 a schematic representation of a hydroformylation reaction; and

2 is a schematic representation of a once-through reactor according to the present invention.

The substrate 1 which, if it is a solid, is dissolved in a suitable solvent is placed in a mixer 2 promoted, which can have a (not shown) stirring device and in which it with a fluid 3 is mixed that the mixer 2 has been supplied from a reservoir via a pump. Mixing the substrate 1 and the fluid 3 can also be done without the use of a stirrer. Hydrogen and carbon monoxide in the form of a mixture 4 become the mixer 2 fed from a reservoir via a compressor and a metering unit (for example an injection valve). The ratio of hydrogen and carbon monoxide can be changed independently as required. The hydrogen / carbon monoxide mixture 4 has a pressure of typically 200 to 220 bar inclusive. This pressure is obtained using a conventional pressure regulator. The addition of dissolved substrate 1 and / or mixture 4 can be continuous or can be done continuously in steps. The hydrogen / carbon monoxide mixture 4 is added via a switching valve or similar control device to the required ratio of the mixture 4 to the substrate 1 to obtain. The ratio of hydrogen and carbon monoxide to the substrate is chosen depending on the reaction to be used and is typically in the range of 1.0: 1.0 to 3.0: 1.0 including equivalents of synthesis gas (ie the mixture 4 ) per reaction.

The temperature and / or pressure of the mixture from the substrate 1 , the fluid 3 and the hydrogen / carbon monoxide mixture 4 are in the mixer 2 to a temperature and pressure near or above the critical point of the fluid as needed 3 set. For this there is a heating device or a cooling device in the mixer 2 intended. The mixture is then fed into the reactor 5 passed, which contains a catalyst (not shown), which is fixed to a suitable support.

After a reasonable dwell time in the reactor 5 becomes the fluid 3 containing the product into a pressure reducing unit 6 headed, and the products 7 after passing through the pressure reducing unit 6 removed via an extraction branch. The flow rate of the reactants through the reactor 5 is from a valve (not shown) in the pressure reducing unit 6 controlled. The amount of material consumed in the reaction and the conversion rate are dependent on the temperature, the feed rate of the substrate 1 in the fluid 3 and the flow rate of the fluid 3 certainly. The fluid 3 together with any unused hydrogen and carbon monoxide through a drain pipe 8th drained for recycling or disposal.

The parameters of a typical implementation could include: a system pressure of 60 to 140 bar (of course this depends in part from the reaction media), a flow rate of the substrate of 0.5 up to 20.0 ml / min, a reactor temperature of 40 to 360 ° C (this again depends partially from the reaction media) and a flow rate of supercritical or near critical fluids from 0.65 to 1.65 l / min; however, these parameters do not imply any restrictions to values within the respective ranges.

Example 1: 5 ml / min oct-1-en is conveyed into a heated mixer, which may have a stirrer where it is mixed with synthesis gas (syngas). The supercritical reaction medium is Koh dioxide, and the system pressure is adjusted via a pressure regulator at the carbon dioxide inlet. The reactor is adjusted to the appropriate temperature (see Table 1) and the mixture is passed through the reactor containing the heterogeneous catalyst (Deloxan HK1 from Degussa). After the reaction, the pressure is lowered through a two-stage expansion valve through which the gaseous carbon dioxide is released, and the products are collected. The products obtained in this reaction under various conditions are shown in Table 1, the analysis of the products being carried out by GC using normalized ranges.

From Table 1 it can be seen that at one given reaction medium a change the temperature and the ratio from substrate to hydrogen and carbon monoxide (synthesis gas) Control the relationship enabled from normal to isocarbonyl product.

Claims (5)

A method of hydroformylating a substrate, the substrate being selected from alkenes, alkynes and trialkylborane and reacting with hydrogen and carbon monoxide in the presence of a heterogeneous catalyst, the substrate being a fluid in its supercritical or nearly critical state and / or the reaction takes place in the presence of a solvent for the substrate, the solvent being in its supercritical or almost critical state, and the process being carried out in a continuous reactor. The method of claim 1, which comprises controlling a or more of the reaction conditions of temperature, pressure, residence time, Flow rate and catalyst has to the yield and / or selectivity to influence the implementation. The method of claim 1 or 2, wherein a solvent is present, which is one or more of: carbon dioxide, one Alkane, ammonia, nitrogen and a saturated halocarbon. The method of claim 1, 2 or 3, wherein the catalyst one or a carrier metal catalyst located. Method according to one of the preceding claims, wherein the catalyst comprises: a carrier that is selected from: an organosiloxane polycondensate, an organosiloxane copolycondensate or polymeric secondary and / or tertiary Organosiloxanamine combinations; and a metal or a metal complex, in which the metal is selected is made of: platinum, nickel, palladium, cobalt, rhodium, iridium, iron, Ruthenium or osmium; and wherein the catalyst is optionally one Has accelerator.